This invention generally relates to elevator door systems. More particularly, this invention relates to an assembly with a unique roller guide for guiding rollers along a rail for moving an elevator door.
Typical elevator door systems include a door frame supported by rollers that roll along a rail so that the door can be moved between opened and closed positions. The rollers typically are driven along the rail using mechanical links, cables, linear motors or other assemblies. In most instances, the rail is made of a metal material while the rollers include a metal or plastic wheel with a flexible material around the circumference of the wheel that rides along the rail. The flexible material is provided on the roller to dampen or reduce noise and vibration during door movement. Another purpose for providing a flexible material around the circumference of the roller is to provide traction control.
One difficulty associated with conventional roller and rail assemblies is that the rail surface is subject to wear and corrosion. Typical rails are made from steel or aluminum and require a surface treatment to resist wear and corrosion. Although various attempts have been made to coat rails, no surface protection method to date has proven completely satisfactory, in part, because of the unavoidable presence of abrasive debris in an elevator hoistway. Coatings are also undesireably expensive.
The challenge of designing a roller and rail system has become further complicated by the introduction of powered rollers for moving elevator doors. In these instances, the roller and rail interaction must not only support the door but also provide sufficient traction for moving the door. Competing design considerations come into play because the roller must maintain a reasonable contact footprint while, at the same time, having a small enough diameter to fit within the available space design constraints of a typical elevator system.
This invention addresses the needs for prolonging the life of the roller and rail system while enhancing available traction and increasing the longevity of the elevator door assembly. This invention avoids the shortcomings and drawbacks described above.